\\[-1.8ex] Soil Heterogeneity & 0.003 & $-$0.023 & $-$0.037 & $-$0.053$^{*}$ & $-$0.053$^{*}$ & $-$0.050$^{*}$ \\ 
  & (0.033) & (0.033) & (0.030) & (0.029) & (0.030) & (0.030) \\ 
\\[-1.8ex] 
Observations & 272,695 & 272,695 & 272,695 & 272,695 & 272,695 & 266,005 \\ 
R$^{2}$ & 0.029 & 0.029 & 0.029 & 0.029 & 0.029 & 0.030 \\ 
